In order to measure a flow rate value remaining in a fuel tank for a ship or a vehicle, a flow meter including a float that ascends or descends or a pressure gauge has been used.
In the case of using the flow meter including the float that ascends or descends depending on an amount of fuel, when shaking of the ship or the vehicle is present, an oil surface is inclined, such that a measurement error of a remaining flow rate occurs. Therefore, it is impossible to accurately measure the flow rate.
The pressure gauge, which is a device calculating a pressure of liquid or gas in a closed container or a pressure generated due to gravity, measures a pressure changed depending on a remaining flow rate in the fuel tank to calculate a remaining flow rate value.
Also in the case of using the pressure gauge, a measurement value of the remaining flow rate is not accurate, and when shaking of the ship or the vehicle is severe, a measurement error of the remaining flow rate becomes large more and more, similar to the case of using the flow meter including the float that ascends or descends.
That is, in the case in which rolling and pitching of the ship due to shaking of water are severe or in the case in which the vehicle is driven on an uphill or a downhill, an oil surface of oil remaining in the fuel tank is inclined, such that it is impossible to accurately measure the remaining flow rate.
In Korean Patent Laid-Open Publication No. 10-2005-0041330 (entitled “Flow Rate Measuring Device of Fuel Tank Using Pressure Sensor” and referred to as Related Art Document 1), a flow rate measuring device of a fuel tank using a pressure sensor including air tubes mounted at multiple places of a corresponding width of the fuel tank and having an internal air pressure changed by an amount of fuel ascending or descending in the air tubes depending on a remaining amount of fuel of the fuel tank, a pressure measuring device measuring a pressure of air changed by the amount of fuel ascending or descending in the air tubes mounted at the multiple places, a controlling unit receiving the pressure of the air measured by the pressure measuring device to calculate a remaining amount of fuel, and a displaying unit receiving a signal of the controlling unit to display the remaining amount of fuel has been disclosed.